Combined sonochemical and short-wavelength UV degradation of hydrophobic perfluorinated compounds

Abstract

Perfluorochemicals (PFCs), which are common in the aquatic environment, are toxic substances that have high chemical and heat resistance because of their strong C-F bonds. We investigated the effect of ultrasonication and short-wavelength UV irradiation on the degradation of perfluorooctane, perfluoropropionic acid, and perfluorooctanoic acid, which are examples of hydrophobic, hydrophilic, and intermediate PFCs, respectively. The results confirmed that ultrasonication was more effective for decomposing hydrophobic PFCs and UV irradiation was more effective for decomposing hydrophilic PFCs. Therefore, defluorination of the degradation intermediates was improved by a combination of ultrasonication and UV irradiation. Our results can be applied to the decomposition treatment of PFCs that have various levels of water solubility in the aquatic environment.

Occurrence, Distribution, and Risk Assessment of Perfluoroalkyl Acids (PFAAs) in Muscle and Liver of Cattle in Xinjiang, China

“…However, lower proportions of less-than 15% were found in the southern and eastern regions, perhaps because extra sunlight leads to direct photolysis of long chain compounds [ 32 , 33 ]. In addition, the intense ultraviolet radiation can also degrade long-chain PFAAs into medium-short substances [ 34 ].…”

Degradation of perfluorooctanoic acid in aqueous solution with sulfate radicals generated in the UV/sodium sulfate system

“…Some advanced oxidation processes (AOPs) in critical conditions have been developed to degrade PFOA. The noticeable treatment technologies are either photo-based approaches, such as: photolysis, photochemical and photocatalysis [7][8][9][10][11] sonochemical treatment [12][13][14][15] or microwavehydrothermal treatment [16][17]. The key factor in these treatment reactions are one-electron oxidants such as persulfate [8][9][10][11][12][13][14][15][16] periodate [10], or photocatalysts such as heteropolyacid [7], TiO2 [9,11], have been used to decompose PFCAs under UV-irradiation.…”

Tailoring photocatalysts and elucidating mechanisms of photocatalytic degradation of perfluorocarboxylic acids (PFCAs) in water: a comparative overview

“…Sonolysis-assisted adsorption of PFCAs was reported to enhance the PFCAs removal capability of GAC. 25 A large number of researches on PFCAs degradation are redox techniques, including thermochemical, [26][27][28] photochemical and photocatalysis, [29][30][31][32][33][34][35][36][37][38] sonochemical treatments, 30,[39][40][41][42][43][44][45][46][47] microwavechemical, 48,49 electrochemical 50,51 treatment processes. They showed promising technology for PFCAs treatment because of high degradation efficiency and defluorination.…”